DE3519064A1 - MULTILAYER, SELF-ADHESIVE AND DRAWN PROTECTIVE FILM, IN PARTICULAR FOR MOTOR VEHICLES - Google Patents

Abstract

The invention describes a multi-ply, self-adhesive and deep-drawable protective sheet, especially for the internal and external outfitting of automotive vehicles, consisting of a carrier sheet containing a thermoplastic synthetic resin based on an ethylene-propylene-diene terpolymer and/or an ethylene-propylene copolymer and a homo- and/or copolymer of propylene, small amounts of fillers and conventional additives; a pressure-sensitive adhesive layer based on an alkyl acrylate and/or methacrylate and/or a copolymerizable, ethylenically unsaturated monomer, such as acylic acid, and a cover layer of a unilaterally siliconized polyolefin film.

Description

MARGOT MÜLLER-GERBES

DIPL.-ING.

RHEINAUSTRASSE 30-32 D-S300 BONN 3 TELEPHONE O2 28-460178 TELEX 6669264 PATD

PH 85032

■ DYNAMIT NOBEL AG, 5210 Troisdorf

AVERY INTERNATIONAL CORPORATION, Wilmington, Del.

United States

Multi-layer, self-adhesive and deep-drawable Protective film, in particular for motor vehicles

The invention relates to a multilayer, self-adhesive and deep-drawable protective film, in particular for the interior and exterior of motor vehicles, consisting of

a carrier layer containing thermoplastic material, Fillers and common additives, a self-adhesive adhesive layer,

optionally a primer layer applied to the carrier layer for the adhesive layer and

a cover layer made of release film or release paper on the adhesive layer.

Multi-layer self-adhesive protective films based on plasticizer-containing EVA-PVC copolymers are for example from DE-OS 32 19 645 known, in particular the protection against falling rocks in motor vehicles serve and are applied as a decorative film. The disadvantage of these films is the polyvinyl chloride content, because at high exhaust gas temperatures there is a risk of the formation of corrosion promoting hydrogen chloride

consists. Furthermore, embrittlement can occur due to the loss of plasticizer, so that the protection against falling rocks decreases, especially at sub-zero temperatures. In DE-OS 28 06 726 a trained as a drone protection Protective layer for motor vehicle floors described the one carrier layer based on polyolefins, in particular Ethylene-propylene rubber, and at least 30% by weight, preferably at least 70% by weight, fillers based on bitumen, softening substances such as oils and acoustically effective minerals such as talc, Schiefj contains flour, graphite, mica. This predominantly soft plastic heavy film that provides soundproofing is permanently connected to the body panel using vulcanization adhesive or heat seal adhesive. The high However, fillers in this film reduce the strength of the film and are beneficial for calendered ones Foils the so-called stress whitening. Since the foils are deformed when they are applied to the body parts, Stress whitening is always undesirable for optical reasons. Protection against stone chipping is also insufficient with this protective layer.

From EP-OS 01 33 23 »are multilayer films for Kraft vehicles also based on internally plasticized vinyl chloride copolymers or based on plasticized polyvinyl chloride, known, which have the same disadvantages as the protective film according to DE-OS 32 19 645 cling.

The invention is based on the object of creating a multilayer protective film that is suitable for both Interior and exterior equipment used in motor vehicles which is designed as a self-adhesive film with good deep-drawability and good strength values with good weather resistance and service life has both at high temperatures and at low temperatures, and in particular a high Has resistance to falling rocks.

An optimal protective film which combines the good properties of the known protective film and which avoids the disadvantages of the same with significantly increased stone chip resistance / is characterized according to the invention in that the carrier film
65 to 25 weight percent ethylene-propylene-diene terpolymer

and / or ethylene-propylene copolymer

35 to 75% by weight homo- and / or copolymer of propylene 0 to 10% by weight fillers such as chalk, carbon black, silica,

Silica anhydride

as well as additionally contains lubricants and stabilizers,

that the adhesive layer consists of a self-adhesive composition based on alkyl acrylates and / or meth ^ crylate and / or copolymerizable ethylenically unsaturated monomers, such as acrylic acid, and is crosslinked that a one-sided siliconized as a cover layer Polyolefin film is provided.

With the invention is a lightweight protective film Made of plastic, which is significantly more flexible than the previously known foils offers increased protection against falling rocks even at sub-zero temperatures. The protective film according to the invention can also in appropriate coloring, in addition to the protective effect at the same time from an aesthetic point of view on the motor vehicle be attached. The protective film according to the invention receives its outstanding properties of deep-drawability, the lightness, the cold impact strength and impact strength through the selected Layers.

The filler-free or almost filler-free according to the invention Carrier film made of EPDM / EPM and polypropylene fulfills in connection with the special adhesive layer and the cover layer a bundle of property requirements that are used in the automotive field ensure a long service life and functionality

These essential required properties that are met by the protective film according to the invention are:

1. Very good stone chip resistance - due to the elastomer Carrier film in connection with the adhesive layer

2. good cold resistance

3. high tear strength and elongation

4. high tear strength

5. Low sensitivity to moisture

6. Good abrasion resistance of the carrier film

7. Good adhesion of the adhesive layer to the carrier film

8. Sufficient gasoline resistance

9. Good light and weather resistance of the carrier film

10. Matt surfaces of the carrier film, suitable for embossing

11. Good deep drawability of the entire multilayer Protective film

12. Temperature resistance of the molded part from the protective film after deep drawing, i.e. good heat dimensional stability

13. No shrinking back under solar radiation of the molded part from the protective film

14. No stress whitening of the carrier film during deformation

15. Preservation of the embossing of the carrier film also during and after deformation

16. easy handling of the protective film when applying the deformed part to the motor vehicle

17. Possibility to easily correct the position when applying the deformed part to the motor vehicle, since the self-adhesive adhesive layer does not become firmly attached until after about 30 minutes, so that the part becomes detached is possible in the attachment phase.

18. Thin protective films mean low weight

19. Corrosion protection

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In a further embodiment of the invention, it is proposed to select those thermoplastic plastics and compounds for the carrier film which enable both the production of the carrier film by extrusion and by calendering / the processing of polypropylene in particular / which tends to stick very quickly is problematic. In order to meet the requirements placed on the processability and the mechanical properties of the carrier film or the protective film as well as possible, a partially crystalline ethylene-propylene copolymer and / or ethylene-propylene-diene terpolymer of 65 to 82 wt. -% ethylene, 18 to 35% by weight propylene, ο to 8% by weight tertiary component, in particular ethylidene norbonene, which has a melt index MFI (230/5) of 0.5 to 2.0 g / 10 min. And a tensile strength of have at least 5 N / mm ² are used. As propylene homopolymer and / or propylene copolymer, preference is given to those with a melt index MFI (190/5) less than 1 g / 10 min. That is, in particular, propylene homopolymers, random propylene copolymers, block propylene copolymers with 5 to 20% by weight of copolymerized ethylene, which have a particularly low melt index. However, during processing, ie production of the carrier film by calendering, it should be noted that polypropylene with an MFI (230 ° C / 21.6 N) of less than 0.1 g / 10 min is no longer suitable for use because it is can not be calendered sufficiently.

Since fillers generally reduce the strength properties of the carrier layer, will Fillers in the protective film according to the invention for the carrier film is only added in small amounts, on the one hand being inorganic powdery Fillers such as chalk, lime, talc or kaolin

can be or, however, preferably also so-called reinforcing fillers such as semi-active or active Carbon black, silica, silicic acid anhydride, glass fibers, or mixtures of the aforementioned fillers. Even Mica or barite can be provided in small quantities.

In addition, the carrier film contains stabilizers and anti-aging agents for polyolefins, in particular based on sterically hindered phenolic antioxidants, phenolic phosphites, thioesters aliphatic carboxylic acids and the like. Metal salts in particular are used as lubricants for processing of carboxylic acids, such as calcium soaps, calcium stearate, zinc stearate and others Processing aids, in particular montanic acid esters and / or hydrogenated hydrocarbon resins, are added.

It is of course also possible to add colorants to the carrier layer, but these are also very finely divided how the other fillers should be, so that they are not detrimental to further processing make it noticeable by deep-drawing the protective film. In addition to dyes, Pigments, such as titanium dioxide, also carbon black are used in small amounts, which also has the Has the advantage of increasing the weathering resistance of the carrier layer. Even a small amount is sufficient here Shares in the carrier layer.

In addition, with regard to the processability of the ethylene-propylene polymers used also softening substances in small amounts, such as aliphatic and / or naphthenic extender oils be added to the carrier layer.

Either preferred embodiment according to the invention of the carrier layer for the protective film with high elastomer proportions, which has particularly good properties in the cold, such as high impact strength by the composition according to the feature of claim 4 from. This is where the carrier layer produced by calendering or extrusion as a film, with calendered films thicknesses from 0.2 mm to 0.75 mm and extruded films thicknesses of about 0.6 mm to about 2 mm. It is possible, then produce particularly thick foils by duplicating or tripling.

For areas of application in motor vehicles that do not require extreme cold impact strength, the invention proposes a somewhat harder carrier film, which is characterized by the features of Claim 5 is characterized.

The carrier film according to the invention can be made particularly effective by embossing the surface with a matt finish or refine a grained structure. This shows the quality of the material of the carrier film, there too during the subsequent deformation of the protective film and carrier film, e.g. by vacuum deep drawing, which Embossing of the surface of the carrier film is perfectly preserved. It is also possible to use the surface to be printed on the carrier film if necessary.

For the adhesive layer are very preferably pressure-sensitive adhesives (pressure sensitive) based on acrylates employed, the ¹ of a usually 30 to 40% adhesive solution with suitable solvents such as isopropanol, hexane, toluene, ethyl acetate, ο. The like. Or mixtures thereof are dissolved and those for crosslinking goeiijiietG crosslinking agents or catalysts, such as retail organic compounds, ζ. Β. Titanium acetylacetonate can be added. This solution is preferably applied to the carrier film.

35190RA

To. When the solvent evaporates, the layers are bonded to form a protective film. In a further embodiment of the invention, it is provided here that the adhesive layer, ie the pressure-sensitive adhesive, is in a thickness which is
Weight per unit area of about 40 to 100 g / m 2 to be applied (solid content). To increase the
The surface of the carrier film to be bonded becomes the adhesive strength between the carrier film and the adhesive layer
appropriately pretreated; preferred by
a corona discharge treatment. It is also possible to apply a suitable primer layer.

The acrylate-based pressure-sensitive adhesives particularly suitable for the invention are shear-stable, age-resistant, permanent, moisture-resistant, solvent- and petrol-resistant, weather-resistant and dimension stable. The pressure sensitive adhesives allow easy attachment and change of position during assembly. Even after the pressure-sensitive adhesive has set, the adhesive formed from the protective film can be used for repairs Part can be removed from the body again with a little effort.

For the protective film according to the invention, a somewhat thicker release film is preferably provided as a cover layer for the adhesive layer, which is particularly good
can also be deformed. For example, polypropylene films are preferred p a thickness of about 50 to 150 .. To the easy peeling of the covering layer before the
To ensure that the part formed from the protective film is adhered to the motor vehicle, the polyolefin film should always have a siliconized side opposite the adhesive layer, in the manner of a release paper.

The protective film according to the invention is used in particular to cover body parts of
Motor vehicles, both outdoors and indoors. Here are preferred

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Preformed / finished trim parts made from the protective film, for example by deep drawing, and applied. On the one hand, they serve to protect against mechanical damage such as stone chips , scratching / and so on, and as corrosion protection. All outer car or body parts that are affected by stone chips, such as door threshold areas, wheel arches, floor and side areas, front sections, can be covered with protective film or parts formed from this. Window frames, areas behind license plates, etc. can also be protected by using the invention. The high flexibility of the protective film allows a high degree of deformation and thus good adaptation to the given shapes. In the interior of the motor vehicle, luggage compartments, vehicle floors, interior door panels, tunnel covers, etc. can be completely or partially covered with the protective film according to the invention. The protective film according to the invention can be colored according to the wishes of the motor vehicle industry. The protective film according to the invention is suitable both for use directly in the manufacture of the motor vehicle and for subsequent application as well as for repairs, even after removing, for example, a damaged protective film area.

An essential property of the protective film according to the invention is its ability to be deep drawn, i.e. the possibility by hot deformation, in particular deep drawing, for example by means of a vacuum against a corresponding one Form to manufacture preformed parts. Here, the protective film according to the invention must be in their The entirety, i.e. with all of its layers, can be thermoformed. Only when the preformed one is applied later Partly from the protective film according to the invention

the cover layer is peeled off and the part is applied firmly to the motor vehicle using pressure. The adhesive layer is adjusted so that it becomes one within a short time after application results in permanent and firm bonding, which, however, requires a certain amount of force for a repair case can be detached again, i.e. that the protective film can be removed again if necessary.

The protective film according to the invention is, however, so largely flexible and deformable that it is at low desired degree of deformation even without preforming on a corresponding area of the motor vehicle can be applied. Both after the deformation, for example by deep drawing, or else even in the case of cold deformation, it retains the shape imposed on it after cooling.

In many cases it is desirable that the protective film or the molded part produced from the protective film have a has an embossed and matt surface. It is an essential part of the protective film according to the invention, that the surface embossed during manufacture, for example after calendering or extrusion retains its embossing through deep drawing, this is due to the good heat resistance of the carrier film .

The invention is shown by way of example in the drawing. Show it

Figure 1 view of the protective film

Figure 2 view of a deep-drawn molded part.

The structure of the self-adhesive multilayer and deep-drawable protective film is schematically shown in FIG 1 shown. The carrier film 2, which is also the protective layer for the part to be protected / for example to form a motor vehicle underbody consists essentially of a calendered or extruded one Plastic film based on EPDM and / or EPM and propylene homopolymer and / or propylene copolymer This carrier film 2, which can optionally be embossed on its top 5, is on its underside with the self-adhesive adhesive layer 3 firmly connected. The self-adhesive adhesive layer 3 is with the cover film 4, covered for example a thin polyolefin film. The multilayer protective film 1 shown in FIG. 1 becomes, for example, a Molded part according to Figure 2 deformed. This deformation can take place, for example, by means of deep drawing, the multilayer protective film preheated to a temperature of about 1-25 to 3-50 ° c and then using a vacuum is deformed against a shape. During this deformation, the top of the carrier film 2 comes to rest form.

It is also possible, however, to likewise apply the multilayer protective film 1 according to FIG. 1 by means of a compression molding press to be pressed into the desired shape while preheating the protective film. For example, as shown in FIG Shaped part la shown is then applied to the corresponding area of the motor vehicle by the cover layer 4, for example, the polyolefin film is peeled off and the molded part la is pressed on. The Ver-

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the bonding takes place within a few

Hours, so that the secure permanent seat of the molded part is guaranteed.

The structure of the multilayer protective film according to the invention is explained below using examples .

The following methods are used to check the properties:

- MFI (190/5) or MFI (230/5) g / 10 min according to DIN 53735

- Tear strength according to DIN 53455

- Elongation at break according to DIN 53455

- Stone impact test with stones according to ASTM D-968 ■ = ■ yield stress DIN 53455

Example 1: Production of the carrier film

60 parts by weight polypropylene copolymer having an ethylene content of 10% and an MFI of 0.8 g / 10 min (190/5) of 40 parts by weight of EPDM having a Mooney viscosity ML (1 + 4) 100 ⁰ C of 85, an MFI (230/5) of 0.8 g / 10 min and an ethylene content of 67% by weight, a propylene content of 30% by weight and an ethylidene norbonene content of 3% by weight with 0.45% by weight . parts stabilizer, 0.15 parts by weight of a lubricant and 2 parts by weight of processed color in a Heizkühlmischer to a free-flowing mixture is plasticized in a twin-screw at temperatures up to 200 ⁰ C and homogenized and fed to a rolling mill. From this, the mass is fed to a calender at a temperature of about 180 ^ 190 ^° C. and drawn out to form a 0.75 mm film. At the outlet of the calender, there is a stamping device with which the desired surface structure is generated at an embossing temperature of about 120 ⁰ C. The film has a tear strength in the longitudinal direction of 28 N / mm ² and an elongation at break in the longitudinal direction of 635%.

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Example 2; Production of a carrier film

47 parts by weight mentioned in Example 1 Polypropylene copolymer are premixed with 53 parts by weight of EPDM's of Example 1 and the remaining pictures of Example 1 in a Heizkühlmischer, a twin-screw extruder fed and plasticized at 170 to 180 ⁰ C and a Rolling mill with temperatures of about 180 to 200 ⁰ C brought. A strainer is used to feed the calender with the ^{mass plasticized to about 190 °} C., which is calendered to a film with a thickness of 0.8 mm with subsequent embossing.

The 0.8 mm thick film has a tear strength in the longitudinal direction of 26.5 N / mm and an elongation at break in the longitudinal direction of 650% and a yield stress in

2
Longitudinal direction of 10.6 N / mm.

Example 3:

42 parts by weight of a polypropylene homopolymer with a density of 0.9 g / ml and an MFI (190/5) of 0.7 g / 10 min. Are premixed with 58 parts by weight of the EPDM from Example 1 in a heating and cooling mixer, Plasticized and homogenized in an internal mixer and fed to the calender via a rolling mill for Foil with a thickness of 0.8mm drawn out and embossed.

The film has a tear strength in the longitudinal

Elongation of 25 N / mm and an elongation at break in the longitudinal direction of 680%.

The carrier films produced according to Examples 1-3 are then applied later with the adhesive layer the side to be connected is subjected to a corona treatment.

On the pretreated side of the carrier film according to Examples 1 to 3, the PSA is made of a 35% solution (35% by weight solids content) of a pressure-sensitive adhesive based on acrylates, such as. B. 52.5 weight

Parts of 2-ethylliexylacrylate, 37.5 parts by weight of methyl acrylate and 10 parts by weight of acrylic acid, and also crosslinking agent, are brushed on, the pressure-sensitive adhesive applied having a basis weight of 60 g / m 2 after the solvent has evaporated and dried. The drying can be carried out from about 60 to 120 ⁰ C at elevated temperatures. The carrier films coated in this way are laminated with the release film to form the protective film by conventional methods. A 80μ or 120μ thick polyethylene or polypropylene film, which is coated on one side with a silicone separating seal, is selected as the separating film or cover layer.

For the production of the cladding parts, punched blanks are made from the protective film according to the configuration of the desired part, which are then deformed to the desired shape ^{in the deep-drawing process, in particular in the vacuum deep-drawing process, with preheating to temperatures of about 120 to 150 ° C.}

The multilayer protective film can be used without any problems, without wrinkles and without stress whitening to show deform.

Also other deep-drawing processes, such as the vacuum pressure process with positive or negative form can be used.

Claims (8)

Claims PH 8ijO32 Multi-layer, self-adhesive and deep-penetrating Protective film / in particular for the interior and exterior fittings of motor vehicles, consisting of a carrier film containing thermoplastic material, fillers and usual additives, a self-adhesive adhesive layer, optionally one applied to the carrier layer Primer layer for the adhesive layer and a cover layer made of release film or release paper on the adhesive layer, characterized in that the carrier film
65 to 25 weight percent ethylene-propylene-diene terpolymer and / or ethylene-propylene copolymer 35 to 75% by weight homo- and / or copolymer of Propylene 0 to 10% by weight fillers such as chalk, carbon black, silica, Silica anhydride as well as contains additional lubricants and stabilizers, that the adhesive layer consists of a crosslinked self-adhesive based on alkyl acrylates and / or methyl acrylate and / or copolymerizable ethylenically unsaturated monomers, such as acrylic acid, and that the cover layer is siliconized on one side Polyolefin film is provided. ORIGINAL INSPECTED 15th 20th 25th 35 - 2 - 2. Protective film according to claim 1, characterized in that g e mark i c h η e t that a partially crystalline ethylene-propylene copolymer for the carrier film and / or ethylene-propylene-diene terpolymer 65 to 82 weight percent ethylene 18 to 35 weight percent propylene 0 to 8 wt -.% Tercomponent with a melt index MFI (230/5) from 0.5 to 2/0 g / 10 min and a tensile strength of at least 2
5 N / mm is used. 3. Protective film according to claim 1 / characterized in that it is a propylene homopolymer and / or propylene copolymer with a melt index MFI (190/5) less than 1 g / 10 min is. 4. Protective film according to one of claims 1 to 3, characterized in that the carrier film by calendering or extruding 60 to 40 w. -% EPDM and / or EPM, 40 to 60 wt .-% homo- and / or copolymer of Propylene 0 to 6% by weight fillers as well as to 100 parts by weight of the aforementioned plastics 0.1 to 1.0 part by weight of stabilizers such as steric hindered phenolic antioxidants, phenolic phosphites, thioesters of aliphatic carboxylic acids ₍ 0.1 to 2 parts by weight of lubricants such as metal salts of carboxylic acids, montanic acid esters, hydrogenated carbon 0 to 5 parts by weight, 0 to 4 parts by weight hydrogen resins' Colorants aliphatic and / or naphthenic extender oils is made in a thickness of about 0.2 to 2 mm and in the longitudinal direction a tensile strength of at least 24 N / mm and an elongation at break of at least 450%. 5. Protective film according to one of claims 1 to 3, characterized in that the Carrier film by calendering or extruding .45 to 25 wt .-% EPDM and / or EPM, 75 to 55 wt .-% homo- and / or copolymer of Propylene
0 to 6% by weight fillers and to 100 parts by weight of the aforementioned plastics 0.1 to 1.0 part by weight of stabilizers such as steric hindered phenolic antioxidants, phenolic phosphites, thioesters aliphatic Carboxylic acids, 2 parts by weight of lubricants such as metal salts of carboxylic acids, montanic acid esters, hydrogenated hydrocarbon resins 5 parts by weight of colorant 4 parts by weight of aliphatic and / or naphthenic extender oils 25 0.1 to 0
0 up to is made in a thickness of about 0.2 to 2 mm and in the longitudinal direction a tensile strength of at least 24 N / mm and an elongation at break of at least 450%. 6. Protective film according to one of claims 1 to 5, characterized in that the adhesive layer in a thickness corresponding to one 2 weight per unit area of about 40 to 100 g / m 2 is provided. 7. Protective film according to one of claims 1 to 6, characterized in that the carrier film is pretreated on the side connected to the adhesive layer by means of corona discharge is. 8. Protective film according to one of claims 1 to 7, characterized in that a polypropylene film with a thickness of about 50 to 150 μ is provided as the cover layer.